Modeling Viscosity of High Titania Slag

Abstract TiO₂-FeO-Ti₂O₃ slag system is the dominant system for industrial high-titania slag production. In the present work, viscosities of TiO₂-FeO and TiO₂-FeO-Ti₂O₃ systems were experimentally determined using the concentric rotating cylinder method under argon atmosphere. A viscosity model suitable for the TiO₂-FeO-Ti₂O₃ slag system was then established based on the modification of the Vogel-Fulcher-Tammann (VFT) equation. The experimental results indicate that completely melted high-titania slags exhibit very low viscosity of around 0.8 dPa s with negligible dependence on temperature and compositions. However, it increases dramatically with decreasing temperature slightly below the critical temperature. Besides, the increase in FeO content was found to remarkably lower the critical temperature, while the addition of Ti₂O₃ increases it. The developed model can predict the viscosities of the TiO₂-FeO-Ti₂O₃ and TiO₂-FeO systems over wide ranges of compositions and temperatures within experimental uncertainties. The average relative error for the present model calculation is < 18.82 pct, which is better than the previously developed models for silicate slags reported in the literature. An iso-viscosity distribution diagram was made for the TiO₂-FeO-Ti₂O₃ slag system, which can serve as a roadmap for the Ilmenite smelting reduction process as well as the high titania slags tapping process.